Rewrite HAOS integration: target-centric architecture with KC color sensors

- Rewrite integration to target-centric model: each picture target becomes
  a HA device under a server hub with switch, FPS, and status sensors
- Replace KC light entities with color sensors (hex state + RGB attributes)
  for better automation support via WebSocket real-time updates
- Add WebSocket manager for Key Colors color streaming
- Add KC per-stage timing metrics (calc_colors, broadcast) with rolling avg
- Fix KC timing fields missing from API by adding them to Pydantic schema
- Make start/stop processing idempotent to prevent intermittent 404 errors
- Add HAOS localization support (en, ru) using translation_key system
- Rename integration from "WLED Screen Controller" to "LED Screen Controller"
- Remove obsolete select.py (display select) and README.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

custom_components/wled_screen_controller/translations/ru.json

@@ -0,0 +1,50 @@
+{
+  "config": {
+    "step": {
+      "user": {
+        "title": "Настройка LED Screen Controller",
+        "description": "Введите URL и API-ключ вашего сервера LED Screen Controller.",
+        "data": {
+          "server_url": "URL сервера",
+          "api_key": "API-ключ"
+        },
+        "data_description": {
+          "server_url": "URL сервера LED Screen Controller (например, http://192.168.1.100:8080)",
+          "api_key": "API-ключ из конфигурационного файла сервера"
+        }
+      }
+    },
+    "error": {
+      "cannot_connect": "Не удалось подключиться к серверу.",
+      "invalid_api_key": "Неверный API-ключ.",
+      "unknown": "Произошла непредвиденная ошибка."
+    },
+    "abort": {
+      "already_configured": "Этот сервер уже настроен."
+    }
+  },
+  "entity": {
+    "switch": {
+      "processing": {
+        "name": "Обработка"
+      }
+    },
+    "sensor": {
+      "fps": {
+        "name": "FPS"
+      },
+      "status": {
+        "name": "Статус",
+        "state": {
+          "processing": "Обработка",
+          "idle": "Ожидание",
+          "error": "Ошибка",
+          "unavailable": "Недоступен"
+        }
+      },
+      "rectangle_color": {
+        "name": "{rectangle_name} Цвет"
+      }
+    }
+  }
+}